Motorcycles are subject to annoying and possibly dangerous wheel vibrations when operated at high speeds if the wheels of the motorcycle are not dynamically balanced. In fact, an unbalanced motorcycle wheel is more noticeable to the operator of a motorcycle than an unbalanced wheel of a passenger car is noticeable to the driver of the passenger car. In addition, inasmuch as a motorcycle is supported by only one wheel at each end thereof, an unbalanced and vertically vibrating wheel of a motorcycle is more dangerous as a result of a reduction of road contact than one or two out-of-balance wheels on a passenger car.
Accordingly, in recent years there has been increased emphasis placed upon proper dynamic balancing of motorcycle wheels. however, the particular manner in which the front wheel of a motorcycle is mounted from the frame thereof poses various problems in the dynamic wheel balancing field which are not associated with passenger car wheel balancing.
The most efficient and least time-consuming manner of dynamically balancing a motorcycle wheel is for the wheel to be spun while mounted on the motorcycle. This type of wheel balancing does not pose any difficult problems when related to the balancing of the rear wheel of a motorcycle, and especially the rear wheel of a motorcycle equipped with a retractable center stand. When a motorcycle is supported on a center stand, a majority of the weight of the motorcycle is disposed forward of the stand and thus the motorcycle is supported with its rear wheel elevated above the ground. Accordingly, a motor driven wheel spinning assembly of the friction drive type may be readily engaged with the rear wheel of the motorcycle in order to spin the latter as required during a wheel balancing operation. However, when the front wheel of a motorcycle is to be spun during a wheel balancing operation some means must be provided to support the motorcycle in a stationary position with the front wheel thereof elevated above the ground. Further, inasmuch as the front wheel of a motorcycle is journaled from the lower end of a front fork assembly which is oscillatably supported from the frame of the motorcycle and rapidly spinning an unbalanced wheel on the front of a motorcycle will cause the front fork assembly to oscillate in a manner which renders a strobe pickup unit attached to the front fork assembly substantially incapable of correctly actuating the strobe light of a wheel balancer in the proper manner to enable a person to determine the proper location upon the motorcycle wheel upon which weights are to be added, a need exists not only for a means to support a motorcycle with its front wheel in an elevated position, but also for a means to securely lock the front fork assembly of the motorcycle against oscillation during the process of spin balancing the front wheel of the motorcycle.
Various types of jack assemblies including braces for bracing a portion of a vehicle to be elevated, vibration indicator and pickup units, and motorcycle and other vehicle jack constructions have been heretofore designed. However, these previous devices have not been specifically designed for use in spin balancing the front wheel of a motorcycle.
Examples of previously patented jacking devices, wheel balancer pickup units and vehicle jacking assemblies which include some components which are remotely similar to the instant invention are disclosed in U.S. Pat. Nos. 2,258,905, 2,288,097, 2,548,809, 2,604,558, 3,203,230, 3,204,933, 3,767,000, 3,772,919 and 3,779,517.